(a) Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a gate oxide layer of a semiconductor.
(b) Description of the Related Art
Oxide layers have been used as a useful insulating layer in technologies for manufacturing semiconductor devices. The oxide layers such as gate insulating layers of MOS transistor devices have been used as an insulating structure for blocking carriers and providing electrical insulation between elements in the semiconductor devices. In addition, the oxide layers have been used as a field structure such as a LOCOS and a trench isolation structure for inhibiting the inadvertent formation of conductive paths between devices in an integrated circuit. In addition, the oxide layers have been used as a diffusion barrier for selectively doping or diffusing a predetermined ion or impurity on a silicon substrate in an ion implanting or diffusing process. Oxide layers have also been used as an etch stopper in dry and/or wet etching processes. As described above, oxide layers have been used for various purposes in semiconductor manufacturing processes because oxide layers are generally not reactive to most chemical solutions.
Oxide layers have various thicknesses according to the uses thereof. For example, an oxide layer used as an interlayer insulating layer generally has a predetermined minimum thickness. On the other hand, an oxide layer used as a gate insulating layer should be relatively thin.
In a case where the oxide layer is used as the gate insulating layer, the quality of the oxide layer and characteristics of devices, as well as the thickness of the oxide layer, are important. In particular, conventionally, an ion implanting process for forming a well region has generally been performed prior to forming the gate insulating layer.
However, in the above cases, there is a problem in that recoiled oxygen is induced by the ion implanting process, so that the thickness of the oxide layer formed in a subsequent process may inadvertently increase. As the projected range Rp (or projected range of implant depth) is lower and ion dose is higher, the amount of recoiled oxygen becomes larger. Therefore, the thickness of the oxide layer may increase and the quality thereof may deteriorate.